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Question 1
Correct
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A 58-year-old man showing symptoms of increase in weight, proximal muscular weakening and withering, easy bruising, and acne. You notice that he has a full, plethoric aspect to his face, as well as significant supraclavicular fat pads, when you examine him. His blood pressure is 158/942Â mmHg, and his glucose tolerance has lately been impaired. His potassium level is 3.2Â mmol/L.What is the MOST LIKELY diagnosis?
Your Answer: Cushing’s syndrome
Explanation:Cushing’s syndrome is a group of symptoms and signs brought on by long-term exposure to high amounts of endogenous or exogenous glucocorticoids. Cushing’s syndrome affects about 10-15 persons per million, and it is more common in those who have had a history of obesity, hypertension, or diabetes.Cushing’s syndrome has a wide range of clinical manifestations that are dependent on the degree of cortisol overproduction. The appearance might be vague and the diagnosis difficult to detect when cortisol levels are just somewhat elevated. On the other hand, in long-term cases of severely increased cortisol levels, the presentation might be colourful and the diagnosis simple.Cushing’s syndrome has the following clinical features:Obesity and weight growth in the true senseSupraclavicular fat pads are fat pads that are located above the clavicle.Buffalo humpFullness and plethora of the face (‘moon facies’)Muscle atrophy and weakening at the proximal levelDiabetes mellitus, also known as impaired glucose toleranceHypertensionSkin thinning and bruisingDepressionHirsutismAcneOsteoporosisAmenorrhoea or oligomenorrhoeaCortisol levels fluctuate throughout the day, with the greatest levels occurring around 0900 hours and the lowest occurring at 2400 hrs during sleep. The diurnal swing of cortisol levels is lost in Cushing’s syndrome, and levels are greater during the whole 24-hour period. In the morning, levels may be normal, but they may be high at night-time, when they are generally repressed. As a result, random cortisol testing is not an effective screening technique and is not advised.The following are the two most common first-line screening tests:Cortisol levels in the urine are measured every 24 hours.A diagnosis of Cushing’s syndrome can be made if more than two collections measure cortisol excretion more than three times the upper limit of normal.Physical stress (e.g., excessive exercise, trauma), mental stress (e.g., sadness), alcohol or drug misuse, complex diabetes, and pregnancy can all cause false positives.Renal dysfunction, inadequate collection, and cyclical Cushing’s disease can all cause false negatives.The overnight low-dose dexamethasone suppression test (LDDST) involves giving 1 mg of dexamethasone at 11 p.m. and measuring blood cortisol levels at 8 a.m. the next day.Cushing’s syndrome is diagnosed when cortisol is not suppressed to less than 50 nmol/L.It might be difficult to tell the difference between mild Cushing’s disease and normal cortisol production.False positives can occur as a result of depression, severe systemic sickness, renal failure, prolonged alcohol misuse, old age, and the use of hepatic enzyme-inducing medicines, among other things.False negatives are extremely uncommon in Cushing’s disease patients.A characteristic biochemical picture might also be helpful in confirming the diagnosis of Cushing’s syndrome. The following are the primary characteristics:HypokalaemiaAlkalosis metabolique
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 2
Incorrect
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Regarding chemical control of respiration, which of the following statements is INCORRECT:
Your Answer: The peripheral chemoreceptors are sensitive to both hypoxia and hypercapnia.
Correct Answer: The blood-brain barrier is freely permeable to HCO3 - ions.
Explanation:CSF is separated from the blood by the blood-brain barrier. This barrier is impermeable to polar molecules such as H+and HCO3-but CO2can diffuse across it easily. The pH of CSF is therefore determined by the arterial PCO2and the CSF HCO3-and is not affected by blood pH.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 3
Correct
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Which statement about cross-sectional studies is true?
Your Answer: They can be used to assess the prevalence of a condition
Explanation:Cross-sectional studies can be used to assess the prevalence of a condition.Cross-sectional studies CANNOT be used to differentiate between cause and effect or establish the sequence of events.They can be used to study multiple outcomes but are NOT suitable for studying rare diseases.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 4
Correct
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A 5-year-old girl presents in a paediatric clinic with symptoms of viral gastroenteritis. You encourage the mother to treat the child at home with oral rehydration therapy (ORT), e.g. dioralyte.Out of the following, which statement is FALSE regarding the use of ORT in the management of gastroenteritis?
Your Answer: ORT is sugar-free
Explanation:One of the major complications of gastroenteritis is dehydration. Choosing the correct fluid replacement therapy is essential according to a patient’s hydration status. Oral rehydration therapy (ORT) refers to the restitution of water and electrolyte deficits in dehydrated patients using an oral rehydration salt (ORS) solution. It is a fluid replacement strategy that is less invasive than other strategies for fluid replacement and has successfully lowered the mortality rate of diarrhoea in developing countries. Some characteristics of Oral rehydration solutions are:- slightly hypo-osmolar (about 250 mmol/litre) to prevent the possible induction of osmotic diarrhoea.- contain glucose (e.g. 90 mmol/L in dioralyte). The addition of glucose improves sodium and water absorption in the bowel and prevents hypoglycaemia. – also contains essential mineral saltsCurrent NICE guidance recommends that 50 ml/kg is given over 4 hours to treat mild dehydration.Once rehydrated, a child should continue with their usual daily fluid intake plus 200 ml ORT after each loose stool. In an infant, give ORT at 1-1.5 x the normal feed volume and in an adult, give 200-400 ml after each loose stool.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pharmacology
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Question 5
Correct
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A 23-year-old male presents to his family physician with the complaint of repeated episodes of abdominal pain and the passage of dark coloured urine every morning. He also reports increasing fatigue over the past several months. On examination, there are raised, painful red nodules over the skin of the back. Laboratory workup shows haemolytic anaemia, leukopenia and thrombocytopenia. Which one of the following disorders is this patient most likely to have?
Your Answer: Paroxysmal nocturnal haemoglobinuria
Explanation:Paroxysmal nocturnal haemoglobinuria is an acquired genetic disorder that causes a decrease in red blood cells due to a membrane defect that allows increased complement binding to RBCs, causing haemolysis. Patients complain of dark-coloured urine first in the morning due to haemoglobinuria secondary to lysis of red blood cells overnight. Thrombosis occurs, which affects hepatic, abdominal, cerebral and subdermal veins. Thrombosis of hepatic veins can lead to Budd-Chiari syndrome, thrombosis of subdermal veins can lead to painful nodules on the skin, and thrombosis of cerebral vessels can lead to stroke. The presence of dark urine in the morning only and at no other time differentiates this condition from other conditions.Multiple myeloma would present with bone pain, signs of radiculopathy if there were nerve root compression and a history of repeated infections. Patients with Non-Hodgkin Lymphoma would complain of enlarged lymph nodes, fatigue, fever, weight loss and a history of repeated infections. Acute lymphoblastic leukaemia presents more commonly in children than in adults. The patient would complain of bone pain, and on examination, there would be hepatosplenomegaly.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 6
Incorrect
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Parasympathetic preganglionic neurons originate in which of the following locations:
Your Answer: CN III, VIII and X
Correct Answer: Brainstem and pelvic splanchnic nerves
Explanation:Parasympathetic preganglionic neurones originate in the brainstem from which they run in cranial nerves III, VII, IX and X and also from the second and third sacral segments of the spinal cord. Parasympathetic preganglionic neurones release acetylcholine into the synapse, which acts on cholinergic nicotinic receptors on the postganglionic fibre. Parasympathetic peripheral ganglia are generally found close to or within their target, whereas sympathetic peripheral ganglia are located largely in two sympathetic chains on either side of the vertebral column (paravertebral ganglia), or in diffuse prevertebral ganglia of the visceral plexuses of the abdomen and pelvis. Parasympathetic postganglionic neurones release acetylcholine, which acts on cholinergic muscarinic receptors.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 7
Incorrect
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After an accidental fall, a 75-year-old patient complains of neck pain and weakness in his upper limbs. Select the condition that most likely caused the neck pain and weakness of the upper limbs of the patient.
Your Answer: Lateral cord syndrome
Correct Answer: Central cord syndrome
Explanation:The cervical spinal cord is the section of the spinal cord that goes through the bones of the neck. It is injured incompletely in the central cord syndrome (CCS). This will result in arm weakness more than leg weakness.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 8
Incorrect
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A fracture on which of the following structures is associated with a posterior elbow dislocation?
Your Answer: Supracondylar
Correct Answer: Radial head
Explanation:Fracture dislocations of the elbow appear extremely complex, and identification of the basic injury patterns can facilitate management. The simplest pattern of elbow fracture dislocation is posterior dislocation of the elbow with fracture of the radial head. Addition of a coronoid fracture, no matter how small, to elbow dislocation and radial head fracture is called the terrible triad of the elbow.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 9
Correct
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A 17-year-old male patient diagnosed with cystic fibrosis is experiencing shortness of breath, coughing, and flu-like symptoms. His X-ray results shows atelectasis, or collapsed lung, specifically in his lower right lung. All of the following statements are true regarding collapsed lungs, except for which one.
Your Answer: Atelectasis is an example of a perfusion defect
Explanation:Atelectasis is a complete or partial collapse of the lung. It occurs when the alveoli deflate or are filled with alveolar fluid. It is considered a ventilation defect of the alveoli due to cystic fibrosis. It is not a perfusion defect. A perfusion defect will produce pathological dead space in which the lung alveoli are ventilated adequately but are not perfused, and there is no gas exchange. While with atelectasis, the alveoli remain perfused. However, there is impaired oxygen delivery and intrapulmonary shunting of blood will be present in the collapsed area. Since there is no exchange of gas at the capillary-alveolar interface of the collapsed segments, the pulmonary capillary blood will have similar PO2 and PCO2.
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This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 10
Correct
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A 63 year old lady presents to ED with a persistent cough and red currant jelly sputum. She has a history of chronic alcohol abuse and has an X-ray which demonstrates a cavitating pneumonia. The most likely causative pathogen is:
Your Answer: Klebsiella pneumoniae
Explanation:One of the results of Klebsiella pneumoniae is pneumonia that is usually a very severe infection. It is characterised by thick, bloody sputum (red currant jelly sputum), and is associated with complications like lung abscess, cavitation, necrosis, empyema and pleural effusions.
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This question is part of the following fields:
- Infections
- Microbiology
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Question 11
Correct
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Regarding cytotoxic T cells, which of the following statements is CORRECT:
Your Answer: They kill target cells by inducing cell apoptosis.
Explanation:CD8+ T-cells (Cytotoxic T cells)Recognise antigen only in association with HLA Class I molecules (found on all nucleated cells; present endogenous antigens such as those found in cells infected by viruses or intracellular bacteria.)Comprise about 25% of peripheral T-cellsResponsible for cytotoxic killing of target cells
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 12
Incorrect
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Regarding loop diuretics, which of the following statements is INCORRECT:
Your Answer: Oral bumetanide acts within 1 hour and diuresis is complete within 6 hours.
Correct Answer: The risk of hypokalaemia is greater with loop diuretics than with an equipotent dose of a thiazide diuretic.
Explanation:Hypokalaemia can occur with both thiazide and loop diuretics. The risk of hypokalaemia depends on the duration of action as well as the potency and is thus greater with thiazides than with an equipotent dose of a loop diuretic. Hypokalaemia is dangerous in severe cardiovascular disease and in patients also being treated with cardiac glycosides. Often the use of potassium-sparing diuretics avoids the need to take potassium supplements. In hepatic failure, hypokalaemia caused by diuretics can precipitate encephalopathy, particularly in alcoholic cirrhosis.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 13
Correct
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Disease specific immunoglobulin is available for all of the following infectious diseases EXCEPT for:
Your Answer: Hepatitis A
Explanation:Disease specific immunoglobulins are available for:hepatitis Brabiestetanusvaricella-zosterNormal immunoglobulin can be used to confer protection against hepatitis A.
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This question is part of the following fields:
- Immunoglobulins And Vaccines
- Pharmacology
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Question 14
Correct
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Flumazenil is a reversal agent for which of the following groups of drugs:
Your Answer: Benzodiazepines
Explanation:Flumazenil is a benzodiazepine antagonist used for the reversal of the sedative effects of benzodiazepines after anaesthesia, sedation and similar procedures.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 15
Incorrect
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A 26-year-old man is involved in a motorcycle accident that results in an open fracture of his tibia and fibula. The nerve that innervates peroneus tertius is damaged as a consequence of his injuries.Peroneus tertius receives its innervation from which of the following nerves? Select ONE answer only.
Your Answer: Tibial nerve
Correct Answer: Deep peroneal nerve
Explanation:Peroneus brevis is innervated by the superficial peroneal nerve.Peroneus longus is innervated by the superficial peroneal nerve.Peroneus tertius is innervated by the deep peroneal nerve.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 16
Correct
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An ambulance transports a 72-year-old woman to the Emergency Department. She is confused, has been vomiting and having stomach pains. Digoxin is one of her medications.Which of the following claims about digoxin is correct?
Your Answer: Therapeutic plasma levels are between 1.0-1.5 nmol/l
Explanation:Digoxin is a cardiac glycoside that is used to treat atrial fibrillation and flutter, as well as congestive heart failure. In cardiac myocytes, it works by inhibiting the membrane Na/K ATPase. Through Na/Ca exchange, this raises intracellular sodium concentration and indirectly increases intracellular calcium availability. Increased intracellular calcium levels have both a positive inotropic and negative chronotropic effect.Digoxin therapeutic plasma levels are typically between 1.0 and 1.5 nmol/l, though higher concentrations may be required, and the value varies between laboratories. At concentrations greater than 2 nmol/l, the risk of toxicity increases dramatically.In patients with normal renal function, digoxin has a long plasma half-life of 36 to 48 hours. This can take up to 5 days in patients with impaired renal function.Hypokalaemia, rather than hyperkalaemia, has been shown to increase the risk of digoxin toxicity.In the treatment of persistent and permanent atrial fibrillation, digoxin is no longer widely used. Beta-blockers, also known as rate-limiting calcium channel blockers, are now the first-line treatment for this condition.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 17
Correct
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Question 18
Correct
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A 72 year old man is brought to ED by ambulance with sudden onset chest pain, palpitations and shortness of breath. His HR is 160 bpm and BP 90/65. ECG demonstrates new-onset fast atrial fibrillation. Which of the following is the first-line treatment option in this case:
Your Answer: Synchronised DC cardioversion
Explanation:All patients with adverse features suggesting life-threatening haemodynamic instability (shock, syncope, heart failure, myocardial ischaemia) caused by new onset atrial fibrillation should undergo emergency electrical cardioversion with synchronised DC shock without delaying to achieve anticoagulation.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 19
Correct
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Diagnosis of HIV is predominantly made through which of the following:
Your Answer: Antibody detection
Explanation:Diagnosis of HIV is predominantly made through detection of HIV antibody and p24 antigen. Viral load (viral PCR) and CD4 count are used to monitor progression of disease.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 20
Incorrect
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Which of the following nerves is responsible for the symptoms of a patient who presented with ophthalmic herpes zoster and a few vesicles on the nose?
Your Answer: Optic nerve
Correct Answer: Trigeminal nerve
Explanation:Hutchinson sign relates to involvement of the tip of the nose from facial herpes zoster. It implies involvement of the external nasal branch of the nasociliary nerve which is a branch of the ophthalmic division of the trigeminal nerve. The nasociliary branch of the trigeminal nerve innervates the apex and lateral aspect of the nose, as well as the cornea. Therefore, lesions on the side or tip of the nose should raise suspicion of ocular involvement.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 21
Correct
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A 53-year-old man arrives at the emergency department complaining of visual impairment in his right eye. On examination, you notice that neither his right nor left pupil constricts when you shine a light in his right eye. When you flash a light in his left eye, the pupils of both his left and right eyes constrict. Which of the following nerves is the most likely to be affected:
Your Answer: Optic nerve
Explanation:In full optic nerve palsy, the afferent pupillary light reflex is lost. Because the afferent optic nerve does not sense light flashed in the afflicted eye, the ipsilateral direct and contralateral consensual reflexes are gone. However, the contralateral direct and ipsilateral consensual reflexes are intact because the efferent oculomotor nerve is normal.
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This question is part of the following fields:
- Anatomy
- Cranial Nerve Lesions
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Question 22
Correct
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What type of visual field defect are you likely to see in a lesion of the visual cortex:
Your Answer: Contralateral homonymous hemianopia with macular sparing
Explanation:A lesion of the visual cortex will result in a contralateral homonymous hemianopia with macular sparing.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 23
Correct
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The following structures all lie anteriorly to the oesophagus EXCEPT for the:
Your Answer: Thoracic duct
Explanation:Posterior to the oesophagus, the thoracic duct is on the right side inferiorly but crosses to the left more superiorly (at T5).
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 24
Incorrect
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The most important Complement protein for antigen opsonization is:
Your Answer: C3a
Correct Answer: C3b
Explanation:Phagocytosis is largely responsible for depletion of cells coated with antibodies. Cells opsonized by IgG antibodies are recognized by phagocyte Fc receptors, which are specific for the Fc portions of some IgG subclasses. In addition, when IgM or IgG antibodies are deposited on the surfaces of cells, they may activate the complement system by the classical pathway. Complement activation generates by-products, mainly C3b and C4b, which are deposited on the surfaces of the cells and recognized by phagocytes that express receptors for these proteins. The net result is phagocytosis of the opsonized cells and their destruction.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 25
Correct
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A patient with diplopia is found to have eye deviation downwards and outwards. The likely nerves that are affected are:
Your Answer: Oculomotor nerve
Explanation:The results of an oculomotor (CN III) nerve palsy are a depressed and abducted (down and out) eye, ptosis, diplopia, and a fixed and dilated pupil.
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This question is part of the following fields:
- Anatomy
- Cranial Nerve Lesions
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Question 26
Correct
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Regarding benzylpenicillin, which of the following statements is CORRECT:
Your Answer: If meningococcal disease is suspected, benzylpenicillin should be given before transfer to hospital.
Explanation:Benzylpenicillin (although inactivated by bacterial beta-lactamases) is effective for many streptococcal (including pneumococcal), gonococcal, and meningococcal infections and also for anthrax, diphtheria, gas gangrene, leptospirosis, and treatment of Lyme disease. If meningococcal disease (meningitis with non-blanching rash or meningococcal septicaemia) is suspected, benzylpenicillin should be given before transfer to hospital, so long as this does not delay the transfer; benzylpenicillin is no longer the drug of first choice for pneumococcal meningitis. Although benzylpenicillin is effective in the treatment of tetanus, metronidazole is preferred. Benzylpenicillin is inactivated by gastric acid and absorption from the gastrointestinal tract is poor and therefore it must be given by injection.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 27
Correct
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A trauma victim who has been intubated is tachycardic, hypotensive, and has a poor urine output. You feel she is dehydrated and decide to use a central venous catheter to help you manage her. As part of this, you keep an eye on the waveform of central venous pressure (CVP).Which of the following cardiac cycle phases corresponds to the CVP waveform's 'a wave'?Â
Your Answer: End diastole
Explanation:The pressure measured in the right atrium or superior vena cava is known as central venous pressure (CVP). In a spontaneously breathing subject, the usual CVP value is 0-8 cmH2O (0-6 mmHg).The structure of the CVP waveform is as follows:The CVP’s components are listed in the table below:Component of the waveformThe cardiac cycle phase.mechanical eventmechanical event Diastole Atrial contractiona wave C  wave v waveEarly systoleThe tricuspid valve closes and bulges Late Systole Filling of the atrium with systolic blood x descenty descentMid systoleRelaxation of the atrium Early diastoleFilling of the ventricles at an early stage
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This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 28
Correct
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In patients requiring oxygen, who are at risk of hypercapnic respiratory failure, oxygen saturations should be maintained at:
Your Answer: 88 - 92%
Explanation:A lower target of 88 – 92% oxygen saturation is indicated for patients at risk of hypercapnic respiratory failure e.g. patients with COPD. Until blood gases can be measured, initial oxygen should be given using a controlled concentration of 28% or less, titrated towards the SpO2 of 88 – 92%. The aim is to provide the patient with enough oxygen to achieve an acceptable arterial oxygen tension without worsening carbon dioxide retention and respiratory acidosis.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 29
Correct
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About case-control studies, one of the following is true.
Your Answer: They are suitable to be used in the study of rare diseases
Explanation:Case-control studies are suitable when investigating a rare disease or in cases where little is known about the disease and the proposed aetiological factor, as a preliminary study. They have the ability to look at multiple risk-factors (exposures) but can only look at a single outcome.In a case-control study, two groups of patients, one with the disease and one without, are compared on the basis of a proposed causative factor that occurred in the past. They are therefore a retrospective study and useful in hypothesis generation.Cohort studies are better at identifying rare exposures. One group with an exposure is compared to a control group without that exposure.Case-control studies are usually less expensive to run and also shorter in duration compared with prospective cohort studies.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 30
Correct
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Approximately how long is the duration of a lidocaine block (when given with adrenaline):
Your Answer: 90 minutes
Explanation:Lidocaine is a tertiary amine that is primarily used as a local anaesthetic but can also be used intravenously in the treatment of ventricular dysrhythmias.Lidocaine works as a local anaesthetic by diffusing in its uncharged base form through neural sheaths and the axonal membrane to the internal surface of the cell membrane sodium channels. Here it alters signal conduction by blocking the fast voltage-gated sodium channels. With sufficient blockage, the membrane of the postsynaptic neuron will not depolarise and will be unable to transmit an action potential, thereby preventing the transmission of pain signals.Each 1 ml of plain 1% lidocaine solution contains 10 mg of lidocaine hydrochloride. The maximum safe dose of plain lidocaine is 3 mg/kg. When administered with adrenaline 1:200,000, the maximum safe dose is 7 mg/kg. Because of the risk of vasoconstriction and tissue necrosis, lidocaine should not be used in combination with adrenaline in extremities such as fingers, toes, and the nose.The half-life of lidocaine is 1.5-2 hours. Its onset of action is rapid within a few minutes, and it has a duration of action of 30-60 minutes when used alone. Its duration of action is prolonged by co-administration with adrenaline (about 90 minutes).Lidocaine tends to cause vasodilatation when used locally. This is believed to be due mainly to the inhibition of action potentials via sodium channel blocking in vasoconstrictor sympathetic nerves.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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SESSION STATS - PERFORMANCE PER SPECIALTY
